1. Open the file sysman/j2ee/config/jazn-data.xml and find the following
section:
<name>ias_admin</name>
<credentials>sometexthere</credentials>
2. Remove the text between the <credentials> and </credentials> tags
and replace with
!your_password (exclamation point followed by your_password)
to reset the password to your_password.
3. Reboot machine to restart EM service.

Upon EM service restart, the "your_password" password will get
encrypted.
You should be able to log in to EM now with the password your_password.